WBC Correction for the Presence of Nucleated Red Blood Cells
Any nucleated red blood cells present in a whole blood sample are not lysed by the diluting fluid
when doing a white blood cell count, either by manual or by automated methods. The nucleated
red cells are counted as white blood cells on the hemacytometer and by the instrument because
they are indistinguishable from small lymphocytes. If five or more nucleated red blood cells
(nRBC) are seen per 100 WBC’s when performing a differential, the total white count MUST be
corrected for the presence of these nucleated red cells. The formula is as follows:
uncorrected WBC count X 100 = corrected WBC count (mm3)
number of nRBC’s per 100 WBC’s + 100
The count should be reported as a corrected WBC count..
Example: 8 nucleated red blood cells are seen while performing a differential on a smear of
peripheral blood from a patient. The leukocyte count reported by the Coulter Counter was
17,400 mm3. What is the actual leukocyte count?
17,400 X 100 = 1740000 = 16,111 mm3 corrected
8 + 100 108
Reference: Rodak, Diagnostic Hematology, 1995, p. 132.
Thursday, July 22, 2010